~Proceedings ICMCISMCI2014 14-20 September 2014, Athens, Greece
Analysis of the Simultaneity, Voice/layer Balance, and Rhythmic Phrasing in
Works for Guitar by Rodrigo, Brouwer, and Villa-Lobos
Sergio Freire
School of Music
Federal University of Minas Gerais
(UFMG)
sfreire@musica.ufmg.br
Lucas Nezio
(graduated at UFMG)
lucasnezio@gmail.com
Anderson dos Reis
School of Music
(UFMG)
andersaosao@hotmail.com
ABSTRACT
The paper analyzes different right-hand guitar techniques,
such as the use of block chords, the balance between independent musical voices and layers, and global rhythmic
control. Three well-known musical excerpts were chosen
from the twentieth-century repertoire for guitar and were
played in three different renditions: the beginning of Rodrigo's Entre Olivares, Brouwer's Etude II and a phrase
from Villa-Lobos's Etude 8. The audio was recorded by
means of an acoustic guitar with hexaphonic pickups, and
data extraction was programmed in Max. Finer timing
adjustments-down to 1 ms-were made manually. At this
scale, we found that block chords are rarely played simultaneously; for the description of this quasi-simultaneity, we
introduced the concepts of spread interval and spread pattern. The excerpts were analyzed also on the note/chord
level and in terms of general rhythmic phrasing. Using
these combined parameters enabled us to explore the technical difficulties and expressive choices in each rendition.
1. INTRODUCTION
There is no novelty or merit in saying that the guitar is able
to deliver more than one sound at the same time. However, taken in isolation, this fact is unable to reveal the
real possibilities the instrument offers for exploring harmony, counterpoint, and other types of polyphony. The
most straightforward approach, the playing of 3- to 6-note
chords, arpeggiated or not, may easily be found in a large
variety of methods of teaching/learning, well known to every beginner. Counterpoint writing and performing is much
more challenging, and everyone minimally acquainted with
keyboard technique will soon discover the drawbacks of
such an exploration on the guitar, mainly when playing
three or more voices. We refer to another type of polyphony
as a "counterpoint of layers" in order to differentiate it
from the regular, baroque-like counterpoint, in which every
voice has a similar status. This type is also very common
on guitar, leading to bass-melody-chords textures, which
present their own demands for players. Extended techCopyright: 2014 Sergio Freire et al. This is an open-access article distributed
under the terms of the C C rr s, which
permits unrestricted use, distribution, and reproduction in any medium, provided
the original author and source are credited.
niques also bring into play new possibilities, such as new
sound typologies and percussive resources.
The guitar affords two distinguishing features: the first
is the set of six strings, with its tuning and its spatial distribution over the fretboard. The second, not completely
independent from the first, is that the right and left hands
have quite distinct functions in producing sound. Typically, the left hand is responsible for changing the length
(tuning) of the strings while the right hand supplies the initial conditions and the energy to the vibrations, both factors
being directly linked to sound quality. Most of the characteristic guitar sound comes from these features.
Musical scores give precise indications for fingering: the
letters p (thumb, from the Spanish pulgar), i (index), m
(middle) and a (ring or annulary) are used for the right
hand fingers. Numbers 1 to 4 are used for the left hand
fingers; numbers 1 to 6 inside a circle indicate the string,
moving from high to low strings; and a zero indicates an
open string.
Until now, systematic approaches to playing polyphony
on the guitar have not been very common. The piano has
a richer literature, owing to the manufacture of the Disklavier by Yamaha since 1987, in different models and degrees of precision [1, 2]. Loic Reboursiere and his group
have issued related works for guitar in Belgium [3] with
hexaphonic pickups, although they are not currently concerned with simultaneity and polyphony. The experimental setup used in the present analysis has already been described in 2013 [4]: hardware items, software, algorithms
for extraction of note onsets, offsets, and amplitudes. Briefly, we developed a real-time procedure for the detection of
onsets, amplitudes, and offsets, using an adaptive comparator of peak and RMS signals, which uses 11 parameters for
each string, and works within an error margin of 10 ms. In
this previous study, we focused on a specific right-hand
technique that is difficult to master, the tremolo, in which
we showed that regularity was never really achieved for all
the parameters analyzed. We now tackle a broader variety
of techniques: block chords, voic-ing control, legato, and
rhythmic phrasing. In this way, we are able to compare not
only technical capacities, but also the musical interpretations the musicians offer in the chosen excerpts.
The excerpts come from twentieth-century guitar literature that is very well known by both professionals and amateurs. The first excerpt, the beginning of Rodrigo's Entre
Olivares [5], which is devoted to block chords, is a techni
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